White Mountains Insurance Group Ltd
WTM- Exchange
- NYSE
- Industry
- Fire, Marine & Casualty Insurance
- SEC CIK
- 0000776867
No open-market purchases or sales by White Mountains Insurance Group Ltd insiders were filed in the last 90 days; 356 institutions reported holding it in 13F filings for Q2 2026, worth $4.57B in total; Southeastern Asset Management (Longleaf) is the only superinvestor holding it.
13F holders, Q1 2026
Institutional positions in White Mountains Insurance Group Ltd as of Mar 31, 2026. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
- Institutional holders
- 368
- +23 vs. Q4 2025
- Shares held
- 2.21M
- +232.8K (+11.8%) vs. Q4 2025
- Total value
- $4.86B
- +$748.7M (+18.2%) vs. Q4 2025
- New holders
- 49
- 120 more added
- Sold out
- 26
- 111 more reduced
8 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q4 2025: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting WTM on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 356 | $4.57B |
| Q1 2026 | 368 | $4.86B |
| Q4 2025 | 353 | $4.67B |
| Q3 2025 | 338 | $3.89B |
| Q2 2025 | 325 | $4.17B |
| Q1 2025 | 322 | $4.44B |
| Q4 2024 | 325 | $4.43B |
| Q3 2024 | 304 | $3.78B |
| Q2 2024 | 306 | $4.14B |
| Q1 2024 | 303 | $4.06B |
| Q4 2023 | 295 | $3.42B |
| Q3 2023 | 272 | $3.40B |
| Q2 2023 | 258 | $3.13B |
| Q1 2023 | 262 | $3.09B |
| Q4 2022 | 265 | $3.20B |
| Q3 2022 | 251 | $2.98B |
| Q2 2022 | 259 | $3.32B |
| Q1 2022 | 244 | $3.09B |
| Q4 2021 | 243 | $2.71B |
| Q3 2021 | 232 | $2.86B |
| Q2 2021 | 233 | $3.11B |
| Q1 2021 | 245 | $3.02B |
Institutions, Q1 2026
Shares, value and share of portfolio for each institution holding White Mountains Insurance Group Ltd; share changes are against Q4 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| Dimensional Fund Advisors LP | 156,618 | $344.1M | 0.07% | +140.0% | Added |
| Neuberger Berman Group LLC | 124,715 | $274.0M | 0.21% | −4,939−3.8% | Reduced |
| River Road Asset Management, LLC | 120,519 | $264.8M | 3.00% | −361−0.3% | Reduced |
| Vanguard Portfolio Management LLC | 115,553 | $253.9M | 0.01% | +115,553 | New |
| BlackRock, Inc. | 113,328 | $249.0M | 0.00% | +1,039+0.9% | Added |
| Vanguard Capital Management LLC | 109,157 | $239.8M | 0.01% | +109,157 | New |
| Cooke & Bieler LP | 104,857 | $230.4M | 2.61% | −1,722−1.6% | Reduced |
| Fuller & Thaler Asset Management, Inc. | 104,561 | $229.7M | 0.77% | −3,611−3.3% | Reduced |
| Fiduciary Management Inc | 85,066 | $186.9M | 2.32% | −5,267−5.8% | Reduced |
| Wallace Capital Management Inc. | 78,795 | $173.1M | 19.88% | −1,552−1.9% | Reduced |
| Morgan Stanley | 59,295 | $130.3M | 0.01% | −22,856−27.8% | Reduced |
| Boston Partners | 57,459 | $126.2M | 0.13% | −19,452−25.3% | Reduced |
| London Co of Virginia | 57,131 | $125.5M | 0.77% | −1,566−2.7% | Reduced |
| State Street Corp | 49,158 | $108.0M | 0.00% | −1,505−3.0% | Reduced |
| Geode Capital Management, LLC | 42,119 | $92.6M | 0.01% | +601+1.4% | Added |
| T. Rowe Price Investment Management, Inc. | 41,513 | $91.2M | 0.06% | −3,047−6.8% | Reduced |
| Gendell Jeffrey L | 37,814 | $83.1M | 1.13% | +5,294+16.3% | Added |
| Reinhart Partners, Inc. | 37,374 | $82.1M | 2.36% | −6,599−15.0% | Reduced |
| Lord, Abbett & Co. LLC | 33,110 | $72.7M | 0.24% | −686−2.0% | Reduced |
| Bank of America Corp | 28,358 | $62.3M | 0.00% | −451−1.6% | Reduced |
| Spears Abacus Advisors LLC | 28,027 | $61.6M | 1.21% | −88−0.3% | Reduced |
| Charles Schwab Investment Management Inc | 24,241 | $53.3M | 0.01% | +1,003+4.3% | Added |
| Raymond James Financial Inc | 23,951 | $52.6M | 0.02% | −18−0.1% | Reduced |
| Mraz, Amerine & Associates, Inc. | 22,179 | $48.7M | 7.18% | −450−2.0% | Reduced |
| Southeastern Asset Management IncSuperinvestorSoutheastern Asset Management (Longleaf) | 18,864 | $41.4M | 2.04% | −12,788−40.4% | Reduced |
| Allspring Global Investments Holdings, LLC | 18,612 | $40.5M | 0.07% | −1,581−7.8% | Reduced |
| Brown Advisory Inc | 17,844 | $39.2M | 0.06% | −1,112−5.9% | Reduced |
| Goldman Sachs Group Inc | 15,783 | $34.7M | 0.00% | +10,523+200.1% | Added |
| Envestnet Asset Management Inc | 15,563 | $34.2M | 0.01% | −235−1.5% | Reduced |
| Northern Trust Corp | 15,495 | $34.0M | 0.00% | −1,172−7.0% | Reduced |
| Vanguard Fiduciary Trust Co | 15,186 | $33.4M | 0.01% | +15,186 | New |
| Wellington Management Group LLP | 14,884 | $32.7M | 0.01% | −1,044−6.6% | Reduced |
| Boussard & Gavaudan Investment Management LLP | 13,975 | $31.0M | 2.97% | +13,975 | New |
| Jane Street Group, LLC | 13,808 | $30.3M | 0.03% | +12,101+708.9% | Added |
| Horizon Kinetics Asset Management LLC | 13,112 | $28.8M | 0.31% | −9−0.1% | Reduced |
| Elkhorn Partners Limited Partnership | 12,700 | $27.9M | 17.76% | −898−6.6% | Reduced |
| Victory Capital Management Inc | 11,145 | $24.5M | 0.02% | +4,849+77.0% | Added |
| SEI Investments Co | 11,098 | $24.4M | 0.02% | +3,182+40.2% | Added |
| Susquehanna International Group, LLP | 10,965 | $24.1M | 0.03% | +10,833+8,206.8% | Added |
| Select Equity Group, L.P. | 10,560 | $23.2M | 0.12% | −9,153−46.4% | Reduced |
| UBS Group AG | 10,441 | $22.9M | 0.00% | +4,440+74.0% | Added |
| Quantinno Capital Management LP | 9,784 | $21.5M | 0.04% | +2,513+34.6% | Added |
| Speece Thorson Capital Group Inc | 9,397 | $20.6M | 4.70% | −1,275−11.9% | Reduced |
| Gotham Asset Management, LLC | 9,047 | $19.9M | 0.06% | +2,331+34.7% | Added |
| D. E. Shaw & Co., Inc. | 8,910 | $19.6M | 0.02% | +317+3.7% | Added |
| Wells Fargo & Company | 8,782 | $19.3M | 0.00% | −359−3.9% | Reduced |
| Bank of New York Mellon Corp | 8,444 | $18.6M | 0.00% | −387−4.4% | Reduced |
| American Century Companies Inc | 8,308 | $18.3M | 0.01% | +7,413+828.3% | Added |
| GW&K Investment Management, LLC | 7,926 | $17.4M | 0.15% | −695−8.1% | Reduced |
| UBS Asset Management Americas Inc | 7,826 | $17.2M | 0.00% | +171+2.2% | Added |
| AQR Capital Management LLC | 7,738 | $17.0M | 0.01% | +3,262+72.9% | Added |
| Thompson Siegel & Walmsley LLC | 7,209 | $15.8M | 0.28% | −1,718−19.2% | Reduced |
| BNP Paribas Arbitrage, SA | 6,623 | $14.6M | 0.01% | +3,283+98.3% | Added |
| Royce & Associates LP | 6,460 | $14.2M | 0.14% | +513+8.6% | Added |
| California Public Employees Retirement System | 6,414 | $14.1M | 0.01% | −302−4.5% | Reduced |
| Hotchkis & Wiley Capital Management LLC | 6,048 | $13.3M | 0.04% | −704−10.4% | Reduced |
| WCM Investment Management, LLC | 5,995 | $13.2M | 0.03% | −4,687−43.9% | Reduced |
| Williams Jones Wealth Management, LLC. | 5,194 | $11.4M | 0.14% | +10.0% | Added |
| Swiss National Bank | 5,036 | $11.1M | 0.01% | −50−1.0% | Reduced |
| Franklin Resources Inc | 4,798 | $10.5M | 0.00% | +4,398+1,099.5% | Added |
| Nuveen, LLC | 4,309 | $9.47M | 0.00% | +834+24.0% | Added |
| Phocas Financial Corp. | 4,292 | $9.43M | 1.48% | −1,199−21.8% | Reduced |
| Rhumbline Advisers | 4,132 | $9.08M | 0.01% | −33−0.8% | Reduced |
| Creative Planning | 4,049 | $8.90M | 0.01% | +634+18.6% | Added |
| Marshall Wace, LLP | 3,878 | $8.52M | 0.01% | +2,780+253.2% | Added |
| Lee Danner & Bass Inc | 3,203 | $7.04M | 0.44% | +100+3.2% | Added |
| Edgestream Partners, L.P. | 3,130 | $6.88M | 0.23% | +2,601+491.7% | Added |
| First Trust Advisors LP | 3,058 | $6.72M | 0.00% | −1,497−32.9% | Reduced |
| Invesco Ltd. | 2,967 | $6.52M | 0.00% | −28−0.9% | Reduced |
| California State Teachers Retirement System | 2,887 | $6.34M | 0.01% | +430+17.5% | Added |
| Ameriprise Financial Inc | 2,866 | $6.30M | 0.00% | −187−6.1% | Reduced |
| Renaissance Technologies LLC | 2,611 | $5.74M | 0.01% | +1,110+74.0% | Added |
| Citadel Advisors LLC | 2,603 | $5.72M | 0.00% | +1,410+118.2% | Added |
| JPMorgan Chase & Co | 2,567 | $5.63M | 0.00% | +761+42.1% | Added |
| New York State Common Retirement Fund | 2,513 | $5.52M | 0.01% | 00.0% | Unchanged |
| Triad Investment Management | 2,513 | $5.52M | 6.52% | −35−1.4% | Reduced |
| MML Investors Services, LLC | 2,459 | $5.40M | 0.01% | −476−16.2% | Reduced |
| Legal & General Group Plc | 2,408 | $5.29M | 0.00% | −629−20.7% | Reduced |
| HRT Financial LP | 2,375 | $5.22M | 0.01% | +2,242+1,685.7% | Added |
| Vanguard Asset Management, Ltd | 2,325 | $5.11M | 0.00% | +2,325 | New |
| State Board of Administration of Florida Retirement System | 2,261 | $4.97M | 0.01% | −531−19.0% | Reduced |
| Dark Forest Capital Management LP | 2,255 | $4.95M | 0.44% | −1,360−37.6% | Reduced |
| Price T Rowe Associates Inc | 2,211 | $4.86M | 0.00% | +221+11.1% | Added |
| Robeco Institutional Asset Management B.V. | 2,179 | $4.79M | 0.01% | +1,556+249.8% | Added |
| Davenport & Co LLC | 2,123 | $4.66M | 0.03% | 00.0% | Unchanged |
| Bradley Foster & Sargent Inc | 2,002 | $4.40M | 0.07% | −3,454−63.3% | Reduced |
| Arrowstreet Capital, Limited Partnership | 1,913 | $4.20M | 0.00% | +1,102+135.9% | Added |
| Parsons Capital Management Inc | 1,888 | $4.15M | 0.19% | +16+0.9% | Added |
| Cerity Partners LLC | 1,867 | $4.10M | 0.01% | −1,676−47.3% | Reduced |
| Atlantic Union Bankshares Corp | 1,765 | $3.88M | 0.07% | 00.0% | Unchanged |
| Colony Group, LLC | 1,129 | $3.82M | 0.00% | −481−29.9% | Reduced |
| Agf Management Ltd | 1,703 | $3.74M | 0.02% | +295+21.0% | Added |
| Regency Capital Management Inc. | 1,535 | $3.37M | 1.51% | −100−6.1% | Reduced |
| Oppenheimer Asset Management Inc. | 1,480 | $3.25M | 0.04% | −22−1.5% | Reduced |
| HighTower Advisors, LLC | 1,447 | $3.18M | 0.00% | 00.0% | Unchanged |
| Citigroup Inc | 1,400 | $3.08M | 0.00% | −449−24.3% | Reduced |
| LPL Financial LLC | 1,395 | $3.07M | 0.00% | −570−29.0% | Reduced |
| CI Private Wealth, LLC | 1,398 | $3.02M | 0.00% | +492+54.3% | Added |
| Toroso Investments, LLC | 1,348 | $2.96M | 0.01% | +1,144+560.8% | Added |
| Stifel Financial Corp | 1,294 | $2.84M | 0.00% | −18−1.4% | Reduced |